Recording head, recording head manufacturing method, combined head and magnetic recording/reproduction apparatus

ABSTRACT

A recording head is a magnetic head in which ends on one side of opposed first and second magnetic cores form a recording gap, said other ends form a magnetic joint, coils insulated by an insulating material are provided between said first and second magnetic cores, magnetic fluxes of said first and second magnetic cores excited by said coils leak from said recording gap so that recording onto a recording medium is carried out. In said recording head, a distance from said end of said recording gap close to said magnetic medium to a contact point of said magnetic joint (hereinafter, yoke length) is not more than 20 μm. A magnetic recording/reproduction apparatus has this head.

This is a divisional of application Ser. No. 09/748,214 filed Dec. 27,2000 now U.S. Pat. No. 6,795,271 the disclosure of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic head for a magneticrecording/reproduction apparatus and a magnetic recording/reproductionapparatus, and more specifically to a recording head, a combined headand a magnetic recording/reproduction apparatus in which a fluctuationin reproduction characteristics is suppressed even in the case where amaterial having great saturation magnetization which realizes highrecording ability is used for a magnetic core.

2. Description of the Related Art

In accordance with a trend of minimization and enlarging capacity of amagnetic memory device, a volume of per one bit to be recorded on amagnetic medium becomes smaller quickly.

A magnetoresistive effect type head (hereinafter, “MR head”) can detecta magnetic signal generated from this minute bit as a large reproductionoutput.

This MR head is discussed as “A Magnetoresistivity Readout Transducer”in “IEEETrans. on Magn,. MAG7 (1971) 150”.

Recently, a great magnetoresistive (hereinafter, “GMR”) head using GMRwhich can realize greatly high output for the MR head has been put intopractical use.

In this GMR effect, particularly a magnetoresistive effect which isgenerally called as a spin-valve effect, in-which a change in resistancecorresponds to cosine between magnetization directions of two adjacentmagnetic layers, shows a great change in resistance in a weak operatingmagnetic field. For this reason, the GMR head using this effect is ageneric name of “GMR head”.

This GMR head using the spin-valve effect is discussed as “Design,Fabrication & Testing of Spin-Valve Read Heads for High DensityRecording” in “IEEE Trans. on Magn,. Vol. 30, No. 6 (1994)3801”.

As for the above GMR head, one magnetic layer of two magnetic layers forproducing the spin-valve effect has a magnetization fixed layer wheremagnetization is fixed so as to be substantially aligned with adirection along which a magnetic field of a medium entering into a headmagnetic sensing portion by an exchange coupling magnetic field which isgenerated by laminating an antiferromagnetic film on the one magneticlayer.

The other magnetic film, which is adjacent to the magnetization fixedlayer via a conductive layer made of Cu or the like, is a magnetizationfree layer in which the magnetization direction can be changed freelywith respect to the magnetic filed of the medium. Hereinafter, the GMRhead using the spin-valve effect is called as “GMR head”.

FIGS. 6 and 7 are structural diagrams showing concrete examples of aconventional combined head 50 which is composed of a GMR reproductionhead 70 and an ID recording head 60. FIG. 7 is a diagram of thestructure of the GMR head viewed from an air bearing surface (ABSsurface) which is a surface opposed to the magnetic medium. FIG. 6 is across section taken along a line A–B of FIG. 7.

Namely, a magnetic separation layer 3 made of an insulating materialintervenes between a lower shield 2 and an upper shield 6 which arelaminated on a ceramic 1 to be used as a slider, and a spin-valvelaminated structure for producing the GMR effect is arranged as a centerarea 4. An end portion area 5 for supplying an electric current and abias magnetic field is formed at both the ends of the center area 4.These are GMR elements for reproduction.

Further, the upper shield is used as a first magnetic core 6, and asecond magnetic core 11 is arranged on a surface of the magnetic core 6which is opposite to the GMR elements via a recording gap 7.

Coils 9, which are sandwiched between the recording gap film 7, anon-magnetic insulating material 10 a and a non-magnetic insulatingmaterial 10 b, are arranged in slightly inner portions of the magneticcores 6 and 11 from ABS.

Recording is carried out by magnetic flux which leaks from the recordinggap 7 between the magnetic cores 6 and 11 magnetized by magnetic fieldsgenerated from the coils.

The above combined-structure head, in which the GMR or MR reproductionhead and the inductive (hereinafter “ID”) recording head are stacked toeach other, is called as a combined head here.

A recording density which is actually used by the combined head usingGMR has a high-density recording area of not less than 3 GB per inch. Aconventional combined head using a material having magnetic anisotropyis sufficient for recording density less than the above density.

Namely, the practical combined head using GMR realizes magneticrecording/reproduction with high density of not less than 3 GB per 1square inch.

In the reverse way, a magnetic recording/reproduction apparatus which isstructured by using the combined head of GMR is an apparatus forcarrying out recording/reproduction with high density of 3 GB per 1square inch.

An ID head which takes responsibility for recording onto a magneticmedium is always required for improvement of a high-density recording.Particularly, a high coercive force of a magnetic medium is essentialfor high-density recording.

This is because a magnetization transition length to be recorded on amedium is made to be shorter in accordance with the improvement of therecording density, or the magnetization is kept constant even if amagnetization length for 1 bit becomes shorter.

For this reason, a technique for increasing a recording magnetic fieldhas been conventionally developed energetically so that recording can becarried out onto high coercive force medium as an ID head which issuitable for high-density recording.

Conventionally, an Ni—Fe plated film (hereinafter, permalloy) in whichNi is about 80 weight % has been used as a magnetic core of the ID head.This material has saturation magnetization (Bs) of about 1 T (tesla),and recording of 3 GB per 1 square inch can be carried out. This isdescribed in “3 Gb/in² recording demonstration with dual element heads &thin film disks” of “IEEE Trans. on Magn,. Vol. 32, No. 1 (1996) pp.7–12”.

However, in order to carry out recording of not less than 5 GB per 1square inch, an Ni—Fe plated film in which Ni is about 45 weight %(hereinafter, 45NiFe) is required instead of the permalloy. This isdescribed in “5 Gb/in² recording demonstration with conventional ARMdual element heads & thin film disks” of “IEEEE Trans. on Magn,. Vol.33, No. 5 (1997) pp. 2866–2871”.

This material has saturation magnetization of about 1.6 T (tesla)maximally. Moreover, with this material, recording of about 12 GB per 1square inch can be carried out. This is described in “12 Gb/in²recording demonstration with SV read heads & conventional narrowpole-tipwrite”of “IEEE Trans. on Magn,. Vol. 32, No. 1 (1996) pp. 7–12”.

Meanwhile, examples using an Ni—Fe plated film in which Bs is about 1.6are disclosed in the Japanese Unexamined Patent Publication (KOKAI) Nos.8-212512 (1996) and 11-16120 (1999).

In addition, an example using a high saturation magnetization Bsmaterial formed by a sputtering method is disclosed in the JapaneseUnexamined Patent Publication (KOKAI) No. 10-162322 (1998), and in thisexample, a Co amorphous film represented by a Co—Ta—Zr sputtering filmis used.

The Co amorphous film can have high Bs up to about 1.5 T. Moreover, theJapanese Unexamined Patent Publication (KOKAI) No. 7-262519 (1995)discloses an application of high Bs materials such as ferric nitride. Itis considered that an iron-nitrogen material can have high Bs of about1.9 T.

Further, in the case where simplicity and cost reduction of amanufacturing process for a magnetic head are considered, it iseffective to form a magnetic material forming a recording magnetic poleaccording to a z plating method.

In the plating method, a photoresist frame through which a form of amagnetic pole previously pierces is formed, and a plated film is allowedto grow in the frame so that a desired pattern can be obtained. Becauseof the simplicity and cost reduction of this method, this method iscurrently a standard manufacturing method of a thin film magnetic head.

Meanwhile, in the case where a magnetic core pattern is formed by thesputtering method, a photoresist mask is formed on a magnetic filmpreviously formed into a core shape, and the core pattern is formed byetching using an ion beam.

In this method, first, an expensive ion beam etching apparatus isrequired, and second, a long processing time is required for patterninga thick magnetic core film of several μm, and third, it is verydifficult to form magnetic core end portions with narrow width whichdetermine a recording width on a medium.

Particularly, as shown in FIG. 6, it is very difficult to pattern theupper core 11 under a condition that there exists a great leveldifference between the coils and their upper and lower insulatinglayers.

The Japanese Unexamined Patent Publication (KOKAI) No. 7-262519 (1995)discloses a method of forming only magnetic core end portions beforeforming a great level difference between coils and insulating layers andintroducing an ion-nitrogen sputtering film into the magnetic core endportions. However, this is originally a method using ion beam etchingand is not a low-priced manufacturing method.

As mentioned above, when the sputtering film is applied to the magneticcore, a rise of the cost due to complication of the manufacturing methodis inevitable.

In addition, in accordance with improvement of the recording density, itis considered that a high Bs film with more than 1.5 T obtained by45Ni—Fe is indispensable. It is very important to realize the high Bsfilm according to the low-priced plating method. Co—Fe—Ni is promisingas a material of a plated film which realize high Bs of more than 1.5 T.

Further, in a composition diagram of three elements in FIG. 1 of theJapanese Examined Patent Publication (KOKOKU) No. 63-53277 (1988), aline of magnetostriction λs=0 in a Co—Fe—Ni plated film is shown, and ina composition diagram of three elements in FIG. 2 of this publication,Bs in the Co—Fe—Ni plated film is shown.

According to this diagrams, Bs around 80Co10Fe10Ni where λs becomesubstantially zero is about 1.6 T.

Meanwhile, in the Japanese Unexamined Patent Publication (KOKAI) No. 6-346202 (1994), crystallizability of the Co—Fe—Ni plated film isadjusted so that both low-magnetostriction and high Bs, which cannot berealized in Japanese Examined Patent Publication (KOKOKU) No. 63-53277(1988), are compatible with each other.

As a result, a Co—Fe—Ni plated film in which Bs is about 1.7 T whenλs<5×10⁻⁶, is obtained.

In addition, the Japanese Unexamined Patent Publication (KOKAI) No.7-3489 (1995) describes that a low coercive force is obtained byadjusting crystallizability and Bs which falls within a range of 1.3 to2 T is obtained.

Further, in Publication of Japanese Patent No. 2821456, a Co—Ni—Feplated film is deposited in a bath without an additive containing S suchas saccharin, and the high-purity film, in which sulfur concentration inthe film is suppressed to not more than 0.1 weight %, is obtained.

As a result, a mixed crystal composition of fcc and bcc transfers to anarea with many Fe compositions, and the magnetostriction is lowered to apractical level in this composition, and extremely high Bs of 1.9 T to2.2 T as well as satisfactory soft magnetic characteristic in which acoercive force is not more than 2.50 e are realized.

As mentioned above, the Co—Ni—Fe plated film can realize the practicalsoft magnetic characteristic as a magnetic core material of ID head bycontrolling crystallizability and content of mixture into the film. Asdisclosed in Patent No. 2821456, Bs can be extremely large andsatisfactory soft magnetic can be realized.

As mentioned above, the Co—Ni—Fe film or 45NiFe film, which is formed bythe plating method and has great saturation magnetization, is verypreferable for a recording core material for achieving high-densitymagnetic recording. However, since these films have the followingproperties, there have conventionally arose various problems due tothese properties.

Namely, the first problem is that the magnetostriction of the Co—Ni—Fefilm or 45NiFe film with high Bs is positive.

For example, in the case where the 45Ni—Fe film is applied to an uppershield of a GMR reproduction head which also serves as a recording core,a fluctuation in a reproduced output after recording operation is veryconspicuous, and thus it becomes a combined head which cannot bepractically used.

This is because as the magnetostriction is positive, a magnetizationstate of the upper shield after recording operation is hardlystabilized, and a reproduction characteristic is adversely affectedtherefrom.

Therefore, the 45NiFe cannot be applied to the upper shield which alsoserves as the magnetic core for recording.

For this reason, the 45NiFe with great saturation magnetization can beapplied only to the upper core, and since normal permalloy is applied tothe upper shield, the recording ability itself is limited.

In addition, as for the Co—Ni—Fe film, its magnetostriction iscontrolled so as to be changed from positive to negative by controllinga composition, but the magnetostriction is positive in the compositionwhere the saturation magnetization is great, namely, not less than 1.7T. Accordingly, the problem which is the same as that of the 45NiFearises.

Further, in the case of the permalloy which has been conventionally usedfor the upper shields, since the magnetostriction of the permalloy filmis controlled by a film composition, it is necessary to strictly controlthe composition so that the magnetostriction suitable for the uppershield is obtained. This causes a rise of the manufacturing cost.

In addition, the second problem is that a stress is strong particularlyin a Co—Ni—Fe film whereby the saturation magnetization is great,namely, about 2 T.

The stress is about 0.8 GPa, and when a thick film of not less than 2 μmis intended to be formed, peeling of the film is conspicuous.

As a result, when the whole upper magnetic core is intended to be formedby a Co—Ni—Fe film which shows great saturation magnetization, the filmthickness of not less than 2 μm is required, and thus the manufacturingis difficult.

As a method of applying the Co—Ni—Fe film to the upper magnetic core, amethod of forming a Co—Ni—Fe film having a thickness of 0.5 μm in avicinity of a recording gap and laminating a permalloy having athickness of about 3.5 μm has been used.

Also with this method, the effect of the material with high saturationmagnetization is successfully brought out, but in order to bring out theeffect maximally it is desirable to form the whole core using a Co—Ni—Fefilm.

Further, the third problem is that as the recording density is improved,the recording head requires an operation with higher frequency.Particularly in a Co—Ni—Fe film where saturation magnetization is large,namely, about 2 T, since a specific resistance is small, namely, about20μΩcm, an overcurrent loss in high-frequency operation increases, andthe recording characteristic is easily deteriorated.

SUMMARY OF THE INVENTION

Therefore, a main object of the present invention is to provide arecording head and a combined head in which the above disadvantages ofthe conventional techniques are resolved and a fluctuation inreproduction characteristic is suppressed even in the case where aCo—Ni—Fe film or a 45NiFe film with great saturation magnetization forrealizing high recording ability is applied to an upper shield of acombined head.

In addition, a second object of the present invention is to provide arecording head in which its high saturation magnetization characteristiccan be applied maximally as recording characteristic by using a magneticcore material with great saturation magnetization such as a Co—Ni—Fefilm or an Ni—Fe alloy film which particularly 1.5 and more saturationmagnetization can be obtained.

In addition, a third object of the present invention is to provide arecording head in which its recording performance is high at highfrequency.

Further, a fourth aspect of the present invention is to provide methodsof manufacturing the above recording head and combined head. This objectis particularly to provide a method of manufacturing a magnetic corewhich enables narrow-width recording according to high-density recordingwhich is realized by applying the recording head of the presentinvention.

Further, a fifth object of the present invention is to provide amagnetic recording/reproduction apparatus provided with the aboverecording head and combined head.

In order to achieve the above objects, the present invention basicallyadopts the following technical structures.

Namely, a first aspect of the present invention is a recording headincluding a magnetic head comprising a first magnetic core and a secondmagnetic core, each being oppositely arranged to each other, one of endsof the first magnetic core forming a recording gap with one of ends ofthe second magnetic core, while the another ends of the first and thesecond magnetic cores forming a magnetic couple, and a coil insulated byan insulating material and provided in a portion formed between thefirst and the second magnetic cores whereby magnetic fluxes of the firstand the second magnetic cores excited by the coil and leaked from therecording gap being used for recording information onto a magneticmedium, wherein a distance L formed between a front end of the magnetichead in proximity of the recording gap and a contact point of themagnetic couple (referred hereinafter to a yoke length), being set atnot more than 20 μm.

Moreover, a second aspect of the present invention is a method ofmanufacturing the above-mentioned recording head including a magnetichead as mentioned above, wherein the method of manufacturing a recordinghead comprises the steps of, the first step of forming a seed layer onan insulating material film, the second step of forming resist patternson the seed layer, the third step of depositing a coil material amongthe resist patterns by means of plating, the fourth step of removing theresist patterns therefrom, the fifth step of removing the seed layerwhich once had been existed under the resist patterns, and the sixthstep of covering the coil material with an insulating material, and notethat in this process, these steps are carried out in this order.

Further, a third aspect of the present invention is a method ofmanufacturing the recording head having a magnetic head therein asmentioned above, wherein the method of forming the coil including thesteps of, the first step of forming an insulation film pattern, thesecond step of forming groove sections for forming coils on theinsulating material film pattern, the third step of forming a seed layeron the insulation pattern where the groove sections have been formed,the fourth step of forming a coil material on the seed layer by means ofplating, the fifth step of removing the coil material formed on aportion other than the groove sections and adjusting a height of thesurface of the coil material formed on the groove sections and a heightof the surface of the insulating material film on the portion other thanthe groove sections so that both heights coincide with each other, andthe sixth step of covering the coil material formed on the portion otherthan the groove sections and the surface of the insulation film on theportion other than the groove sections with an insulation material, andnote that in this process, the above-mentioned steps are carried out inthis order.

On the other hand, a fourth aspect of the present invention is acombined head which is configured so that one of the first and secondmagnetic cores in the above-mentioned recording head, is commonly usedas a first magnetic shield, while a reproduced process can be carriedout by a magnetoresistive effect element which is provided between thefirst magnetic shield and a second magnetic shield oppositely arrangedto the first magnetic shield.

A fifth aspect of the present invention is a magneticrecording/reproduction apparatus which is provided with the combinedhead as mentioned above.

Since the recording head, the combined head and the magneticrecording/reproduction apparatus of the present invention adopt theabove-mentioned technical structure, even if Co—Ni—Fe film or 45NiFefilm having a large amount of saturation magnetization for realizinghigh recording ability is applied to an upper shield of the combinedhead, the recording head and the combined head in which a generation ofa reproduction noise is suppressed, can be realized.

At the same time, a recording head in which a characteristic ofhigh-saturation magnetization saturation can be maximally utilize as arecording characteristic, by using a magnetic core material havingrelatively large amount of saturation magnetization, particularly byusing a Co—Ni—Fe film whereby saturation magnetization of not less than1.5 can be obtained, can be realized.

Particularly in Co—Ni—Fe film or Ni—Fe alloy film having Bs of not lessthan 1.7, as Bs becomes higher, magnetostriction has a tendency toincrease towards positive, and thus there arises a problem that areproduction noise increases. However, with the structure of the presentinvention, since a reproduction noise can be suppressed even when amaterial having large amount of magnetostriction is used, a film havinghigher Bs can be applied to the magnetic cores.

In addition, the recording head, the combined head and the magneticrecording/reproduction apparatus of the present invention can realize astorage device which having large large capacity and being suitable forrecording, reproduction and transmission of high speed data, because theabove-mentioned recording head, the combined head and the magneticrecording/reproduction apparatus having high recording performance athigh frequency and also having a narrow track width suitable forhigh-density recording.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section showing a structure of a recording headaccording to a first embodiment of the present invention;

FIG. 2 is a plan view showing a structure viewed from an ABS surface ofthe recording head according to the first embodiment of the presentinvention;

FIG. 3 is a cross section showing another structure of the recordinghead according to the present invention;

FIG. 4 is a cross section showing another structure of the recordinghead of the present invention;

FIG. 5 is a cross section showing a structural example of a combinedhead of the present invention;

FIG. 6 is a cross section showing a structure of one example of aconventional combined head;

FIG. 7 is a plan view showing a structure viewed from an ABS surface ofthe conventional combined head shown in FIG. 6;

FIG. 8 is a structural diagram viewed from an ABS surface of a combinedhead according to a second embodiment of the present invention;

FIG. 9 is a cross section showing the combined head according to thesecond embodiment of the present invention;

FIG. 10 is a cross section showing another structure of the combinedhead according to the second embodiment of the present invention;

FIG. 11 is a structural diagram viewed from an ABS surface of a combinedhead according to a third embodiment of the present invention;

FIG. 12 is a cross section of the combined head according to the thirdembodiment of the present invention;

FIG. 13 is a structural diagram viewed from an ABS surface of a combinedhead according to a fourth embodiment of the present invention;

FIG. 14 is a cross section of the combined head according to the fourthembodiment of the present invention;

FIG. 15 is a cross section of a combined head according to a fifthembodiment of the present invention;

FIG. 16 is a structural diagram viewed from an ABS surface of a combinedhead according to a sixth embodiment of the present invention;

FIG. 17 is a cross section of the combined head according to the sixthembodiment of the present invention;

FIG. 18 is a diagram showing a relationship between an outputfluctuation and a yoke length L according to a recording operation;

FIG. 19 is a diagram showing a relationship between a frequency of aninductance which is reduced 30% and a yoke length;

FIG. 20 is a diagram showing a relationship between recording magneticfield and saturation magnetization×film thickness of a magnetic core;

FIG. 21 is a diagram showing a relationship between recording magneticfield and saturation magnetization×film thickness of the magnetic core;

FIG. 22 is a diagram showing a relationship between recording magneticfield and saturation magnetization×film thickness of the magnetic core

FIG. 23 is a diagram showing a relationship between peeling incidenceand a film thickness of a magnetic core film (saturation magnetizationis constant, i.e., 2 T);

FIG. 24 is a diagram showing a range of the yoke length L and saturationmagnetization×film thickness according to the present invention;

FIG. 25 is a diagram showing insulation percent defective and apositional relationship between a coil and an insulating film;

FIG. 26 is a diagram showing a relationship between the insulationpercent defective of the coil and insulating layer thickness (h)/coilthickness (d) on the coil;

FIG. 27 is a cross section showing that a photoresist for forming amagnetic core is applied to a coil/insulating material structure;

FIG. 28 is a diagram showing a slider to which the combined head of thepresent invention is mounted;

FIG. 29 is a structural diagram showing a structure of a magneticrecording/reproduction apparatus according to one embodiment of thepresent invention;

FIGS. 30( a) through 30(f) are step diagrams showing examples of thesteps of manufacturing the recording head of the present invention;

FIGS. 31( a) through 31(h) are step diagrams showing another examples ofthe steps of manufacturing the recording head of the present invention;

FIG. 32 is a graph showing a relationship between the output fluctuationand the yoke length L according to the recording operation of therecording head of the present invention where magnetostriction is shownas a parameter;

FIG. 33 is a graph showing a relationship between a coil width and theoutput fluctuation in relation with the recording head of the presentinvention; and

FIG. 34 is a plan view showing an example of a wiring pattern of coilsformed in the recording head of the present invention.

FIG. 35—39 present Tables 1.1—3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific embodiments of a recording head and a manufacturing methodthereof according to the present invention will be explained hereunder,with reference to the drawings.

Namely, FIG. 1 is a cross section showing a structure of one embodimentof the recording head of the present invention.

In FIG. 1, ends 61 on one side of a first magnetic core 6 and a secondmagnetic core 11 which are opposed to each other, form a recording gap7, and the other ends 62 thereof, form a magnetic coupling 63, and coils9 which are insulated by an insulating material 10 are provided betweenthe first magnetic core 6 and the second magnetic core 11.

Magnetic fluxes generated from the first and second magnetic cores 6 and11 excited by the coils 9, leak from the recording gap 7 so that amagnetic head 60 carries out recording onto a magnetic medium 31,utilizing thus leaked magnetic fluxes.

The recording head 60 is constituted so that a distance L (hereinafter,yoke length) from an end portion 64 of the recording gap proximity tothe magnetic medium 31 to a contact point 65 of the magnetic coupling 63is set to not more than 20 μm.

In addition, FIG. 3 shows another structural example of the recordinghead 60 according to the present invention and shows a case where aphotoresist 8 is arranged under the coil as a lower side insulatingmaterial which covers the coils 9.

Moreover, FIG. 4 shows still another structural example of the recordinghead 60 according to the present invention and shows a case where thecoils 9 has a configuration of two-layered structure.

FIGS. 1, 3 and 4 show names of respective parameters defined in therecording head 60 of the present invention.

Note that, in the above embodiments, the yoke length L is a length froman ABS surface 40 of the magnetic core 11 to the point 65 at which themagnetic core 11 contacts with the magnetic core 6.

Distances from an end portion of the outermost coil to the end portionsof insulating materials 10, 10 a and 10 b which covering the coils fromthereabove as shown in Figs as mentioned above, are represented by W1,W2, W1′ and W2′.

Thicknesses of the insulating materials 10, 10 a and 10 b covering thecoils 9 and existing upon a top surface of the coils 9 as shown in theabove-mentioned Figs, are represented by h and h′.

In addition, in the recording head 60 of the present invention, it isdesirable that a portion of at least one of the first and secondmagnetic cores 6 and 11 opposed to each other and in a vicinity of therecording gap, is composed of a magnetic material, which mainly containsat least two kinds of elements selected from a group consisting of Co,Fe and Ni and has saturation magnetization of not less than 1.5 T.

Further, in the recording head 60 of the present invention, it isdesirable at least one of the first and second magnetic cores opposed toeach other has a configuration in that a plurality of magnetic materiallayers each having saturation magnetization the respective amount ofwhich being different from each other and further it is also desirablethat the saturation magnetization of the magnetic material layer locatedin the vicinity of the recording gap is set at a value thereof greaterthan that of the saturation magnetization of the magnetic material layerwhich is arranged at a portion far from the recording gap.

In this case, it is desirable that the magnetic material arranged at aportion in the vicinity of the recording gap mainly contains at leasttwo kinds of elements selected from Co, Fe and Ni and the saturationmagnetization thereof is set at a level of not less than 1.5 T.

In addition, in the recording head 60 of the present invention, it ispreferable that with respect to the yoke length L (unit: μm), a productof said saturation magnetization (unit: T) and the film thickness (unit:μm) of the magnetic materials composing each one of said first andsecond magnetic cores 6 and 11 opposing to each other, respectively,satisfies the following relationship:0.05 (T)×yoke length L (μm)+0.5 (T·μm)≦saturation magnetization (T)×filmthickness (μm).

In addition, more preferable condition satisfies the followingrelational expression:0.05 (T)×yoke length (μm)+0.5 (T·μm)≦saturation magnetization (T)×filmthickness (μm)≦4 (T·μm).

The inventors of the present invention conducted various experiments inorder to solve the above-mentioned problems of the conventionaltechnique and achieved the present invention.

Note that, the inventors understood that a Co—Ni—Fe film or a 45NiFefilm with great saturation magnetization for realizing high recordingability which is the above main object of the present invention isarranged in the vicinity of the recording gap in the upper shield or themagnetic core of the recording head so that the recording head and thecombined head in which a fluctuation in reproduction property issuppressed can be manufactured.

However, it was found that at this time various technical problemsarise, and thus it is necessary to examine countermeasures against theproblems.

Therefore, the inventors created samples as shown in Tables 1 through 3.These samples are magnetic heads in which both of the magnetic coresused as an upper core and the magnetic core used as an upper shield in amagnetic head, were formed respectively by selecting each one of a filmstructures among various film structures as shown in Tables 1 through 3.

The inventors had manufactured various kinds of magnetic heads usingthese samples, as shown in the above mentioned Tables.

The samples were obtained in such a manner that various permalloy filmsand magnetic films, in which a structural ratio of compositions of Co,Ni and Fe was variously changed, were manufactured by a plating methodor a sputtering method.

In addition, saturation magnetization (T), magnetostriction, specificresistance and film thickness of the respective sample films werechanged as shown in Table 1, and the yoke length L in the case wheremagnetic heads were manufactured by using the sample films as mentionedabove, was also changed variously.

Particularly as for the yoke length L, as described in Tables 1 through3, magnetic heads, in each of which, the yoke length L had beenvariously changed in a range of 5 μm to 75 μm, were manufactured, andinfluences upon the recording head 60 in the case where the yoke lengthwas changed, was examined.

Here, with regarding the coils composing the magnetic head, a patternform as shown in FIG. 34 had been used and the pattern form thereof hadbeen reduced or enlarged in accordance with the yoke length L.

Measurements were made under such condition in which a magnetic fieldstrength (coil winding number×electric current) generated from the coilsbecomes uniform.

At first, in the first embodiment of the present invention andcomparative examples 1, 2 and 3 shown in Table 1, as shown in FIGS. 2and 5, as for the structure of the magnetic head, the-coil has atwo-layers form, in that the magnetic core 6 is composed of atwo-layered magnetic film, while the magnetic core 11 composing theupper shield is composed of a single-layered magnetic film.

In addition, in a second embodiment of the present invention as shown inTable 2 and comparative examples 4 through 14 as shown in Table 1, themagnetic head has a configuration as shown in FIGS. 8 and 9, the coilhas a single-layered form, and the magnetic core 6 is composed of atwo-layered magnetic films, and the magnetic core 11 composing the uppershield, is also composed of a two-layered magnetic films.

In addition, in a third embodiment of the present invention as shown inTable 2, as shown in FIGS. 11 and 12, regarding the structure of themagnetic head, the coil has one-layered form, the magnetic core 6 iscomposed of a single-layered magnetic film, and the magnetic corell,composing an upper shield, is also composed of a two-layered magneticfilms.

Further, in a fourth embodiment of the present invention as shown inTable 2, as shown in FIGS. 13 and 14, regarding the structure of themagnetic head, the coil has one-layered configuration, and the magneticcore 6 is composed of a single-layered magnetic film, and the magneticcore 11 composing the upper shield, is also composed of a single-layeredmagnetic film.

Further, in a fifth embodiment of the present invention and acomparative example 15 as shown in Table 3, as shown in FIG. 15,regarding the structure of the magnetic head, the coil has one-layeredform, and the magnetic core 6 is composed of a two-layered magneticfilm, while the magnetic core 11 composing the upper shield, is composedof a single-layered magnetic film.

In addition, evaluations of the respective samples as shown in Tables 1through 3, adopt a degree of output fluctuation, 30% Roll-off frequencyof 100 MHz and 0/W value (dB), mentioned later.

The evaluations were made on a basis that the recording head showssatisfactory characteristic in the case where the degree of outputfluctuation is not more than 1.0%, the 30% Roll-off frequency is notless than 100 MHz and the overwrite 0/W value (dB) is not less than 30.

In addition, a condition regarding the recording/reproduction wasevaluated under conditions that a coercive force of the magnetic mediumwas 4000 Oe and a magnetic spacing was 35 nm.

At first, a judgment was made from respective characteristic values inthe first embodiment.

It was found that when the yoke length was not more than 19 μm, themagnetic head showed satisfactory characteristic in that the degree ofoutput fluctuation will be explained later, was not more than 1.0% andthe 30% Roll-off frequency was not less than 100 MHz, regardless of thestructure of the magnetic film as well as its manufacturing method.

On the contrary, as shown in the comparative example 1, it was foundthat when the yoke length was long, the frequency characteristic wasparticularly deteriorated.

In addition, it is understood that even in the case where a 45NiFe filmwas used for the upper core 11 and the magnetostriction value of the45NiFe film is 15×10⁻⁶, the magnetic head shows satisfactorycharacteristic.

In the comparative examples 2 and 3, even though the sample thereof hadthe structure which are the same as that in the first embodiment of thepresent invention, since the thickness of the magnetic core 11 composingthe upper shield, was too thin and thus the 0/W value (dB) becameremarkably small, the magnetic head of the comparative examples 2 and 3showed the characteristics not suitable ones for magnetic head.

Next, according to the results of the second embodiment of the presentinvention and the comparative examples 4 through 14 where the yokelength L is changed in a range of 23 μm to 75 μm, the output fluctuationaccording to the recording operation and the 30% Roll-off frequencycharacteristics are evaluated with respect to the yoke length, and theevaluated results are shown in FIGS. 18 and 19.

“The output fluctuation according to the recording operation” heredenotes a ratio of a standard deviation of the reproduction output to anaverage value of the reproduction output (“standard deviation”/averagevalue of reproduction output”) when the reproduction output is measuredevery after the recording operation had completed.

In this experiment, as shown in FIGS. 8 and 9, in a combined head 50, aCo—Ni—Fe film having saturation magnetization a value of which beingstrong and magnetostriction being positive, was arranged in a magneticcore 6 a and a magnetic core 11 a located at a portion in a vicinity ofa recording gap 7.

Moreover, a permalloy film was arranged on a magnetic core 6 b and amagnetic core 11 b which are located at a portion far from the recordinggap 7.

As is clear from FIG. 18, it is apparent that when the yoke length L isshortened so that it is set at a length being not more than 20 μm, theabove-mentioned output fluctuation accompanied with the recordingoperation is reduced.

Although it had not been pointed out about the noise reduction effect byshortening the yoke length L, in the past, it was found by the presentinvention that such noise reduction effect by shortening the yoke lengthL is actually remarkable.

As shown in FIG. 18, when the yoke length is not more than 20 μm, theoutput fluctuation becomes not more than 1% (“standarddeviation”/average value of reproduction output“≦0.01”).

This standard is such that the influence of the recording operation ofthe recording head can be almost ignored.

Meanwhile, FIG. 19 shows a frequency at which the inductance on ahigh-frequency side can be reduced upto 30% with respect to the one on alow frequency side (called as “30% Roll-off frequency”) when a frequencycharacteristic of an inductance is measured in the combined head wherethe yoke length L is changed (the structure is shown in FIGS. 8 and 9).

Here, a reason why the 30% Roll-off frequency was taken as a standard ofa high-frequency characteristic, is such that it was found that anon-linear-transition-shift (NILTS) of the recording/reproductioncharacteristics was less than 20% when the frequency at which aninductance can be reduced by about 30%, is used, and thus the frequencycan fall within a satisfactory range as a recording/reproduction system.

In the present invention, the case where the 30% Roll-off frequency isnot less than 100 MHz was evaluated as a suitable characteristic of themagnetic head.

As is clear from FIGS. 18 and 19, it was confirmed that the yoke lengthL of the magnetic head was shortened so that the high-frequencycharacteristic was improved, and particularly the improvement when theyoke length L is not more than 20 μm was remarkable.

Note that, a cause of the reduction in the output fluctuation due to theshortening of the yoke length L is assumed that qualitatively aninfluence of effective magnetostriction was reduced by a reduction in avolume of the upper shield to be magnetized at the time of the recordingoperation.

However, it is quantitatively difficult to estimate how much influenceof the reduction in the volume is given substantially as a fluctuationin the reproduction output.

This has never been estimated.

The relationship between the output fluctuation and the yoke length L isquantified at first by the experimental results of the presentinvention.

The above results show that even if the magnetic film whosemagnetostriction is positive, is arranged on the upper shield, theinfluence of the recording operation which affect on the reproductioncharacteristic can be made sufficiently small.

Note that, in the case where only a permalloy film is applied to theupper shield like the conventional technique, control of a filmcomposition can be loosened, and production yield can be improved.

In addition, since the Co—Ni—Fe plated film to be used in theembodiments of the present invention (a composition ratio of theelements is such that Co is 60 to 70 wt %, Fe is 15 to 30 wt % and Ni is5 to 15 wt %) has a film having high Bs, it is suitable for high-densityrecording, but magnetostriction and stress are strong.

For this reason, this material is particularly preferable forapplication of the technique of the present invention.

Further, as is clear from the above embodiments, it is found that eventhe Fe—N film formed by the sputtering method can achieve the object ofthe present invention.

Meanwhile, FIGS. 20, 21 and 22 show a relationship between the recordingmagnetic field strength generated from the recording gap and a productof the saturation magnetization and film thickness of the magnetic core(simulation result) when the yoke length L is set at value such as 5 μm,10 μm and 20 μm that are seemed to be a short length.

At this time, a length and a depth of the recording gap were set to beconstant.

In addition, generated magnetic field of the coils of the respectivehead (coil winding number×electric current flowing in coils) were set tobe constant.

Further, the magnetic field strength is standardized by a saturationvalue.

As known with reference to the respective diagrams, saturationmagnetization that the recording magnetic field strength issaturated×film thickness, becomes 0.75 (T·nm) when the yoke length is 5μm, becomes 1.00 (T·nm) when 10 μm, and 1.5 (T·nm) when 20 μm, showingthat the value of the product is increased as the yoke length becomeslonger.

It is found that when a value of the saturation magnetization×filmthickness would take a value exceeding than the above values withrespect to the respective yoke lengths, the recording magnetic fieldstrength is saturated, namely, sufficient recording magnetic field isobtained.

Note that, when judged from the above results, it is found that in thecase where the saturation magnetization is set to be constant, as theyoke length is shorter, the thickness of the magnetic film can bethinner. Namely, it is necessary to set suitable film thicknesses withrespect to the yoke lengths.

Thinning of the upper shield is required for bringing a reproduction gapclose to a recording gap in accordance with the improvement of therecording density.

Conventionally, as shown in the results, there has been tendency for theoutput fluctuation after the recording operation to be larger when theupper shield is thinner becomes larger. Therefore, it is found that theyoke length L is set to be short, namely, not more than 20 μm, so thatthe combined head where the output fluctuation is suppressed can beprovided even if a thickness of film used for the upper shield isthinned.

Further, judging from the above results, as the film thickness of themagnetic core is the thinner, the influence of the overcurrent lossbecomes the smaller.

In addition, since the width and film thickness of the yoke can be smallby shortening the yoke length L, the volume of the magnetic core can bereduced remarkably.

As a result, it is considered that as the yoke length L is shortenedfurther in order to reduce the overcurrent loss in high frequencygreatly, the high-frequency characteristic is improved remarkably.

However, from the viewpoint of practical use, the recordingcharacteristic in a frequency bandwidth to be used may be satisfied, andthe thickness thereof may be set at any value of thickness for easymanufacturing as long as the above recording characteristic issatisfied.

In the case where the magnetic core film is formed by the platingmethod, when the film thickness becomes too thin, it is difficult tocontrol the film thickness. Therefore, that the film to be used andhaving a thickness with some extent, is also advantageous tomanufacturing.

Further, FIG. 24 shows a relationship among the yoke length L and thesaturation magnetization and the film thickness which shows a preferablecharacteristic of the recording heads obtained from the characteristicdata relating to the recording heads of the respective embodiments.

Namely, FIG. 24 is a graph showing a preferable magnetic core area basedon the above-mentioned experimental results.

That is, it is shown that the preferable area of FIG. 24 is set so thatthe yoke length L is not more than 20 μm, the magnetic core satisfies arelationship of 0.05 (T)×yoke length L (μm)+0.5 (T·μm)≦saturationmagnetization (T)×core film thickness (μm).

Note that, the result in FIG. 24 includes a case where the magnetic coreis composed of an lamination formed by a plurality of magnetic materialfilms.

That is, in the case where of two-layered magnetic film, the value ofthe saturation magnetization (T)×core film thickness (μm) is a value ofa total sum Σ of products each comprising a product of saturationmagnetization (T) of the respective magnetic material forming a part ofthe magnetic core×core film thickness (μm) thereof, namely a total sum Σof (saturation magnetization (T)×core film thickness (μm)).

In this case, it is desirable for the magnetic core to be set to satisfya relationship, such as 0.05 (T)×yoke length L (μm)+0.5 (T·μm)≦Σ(saturation magnetization (T)×film thickness (μm)).

Further, in the case of the Co—Ni—Fe plated film having a largesaturation magnetization is used, its stress will arises a furtherproblem.

For example, since the Co—Ni—Fe plated film having the saturationmagnetization of 2 T occasionally has a stress of about 0.8 GPa, if thefilm was too thick, the film would be peeled.

FIG. 23 is a diagram showing a relationship between the film thicknessand film peeling incidence of the Co—Ni—Fe plated film having saturationmagnetization of 2 T.

As understood from the diagram, when the film thickness exceeds 2 μm,peeling abruptly occurs.

As a result, in the present invention, in the case where the Co—Ni—Feplated film having high Bs is used, it is desirable that the yoke lengthL is set to be not more than 20 μm and the magnetic core satisfies therelationship: 0.05 (T)×yoke length L (μm)+0.5 (T·μm)≦(saturationmagnetization (T)×core film thickness (μm)≦4(T·μm).

As mentioned above, in the respective samples shown in Tables 1 through3, in the case of the coils whose winding number is 5 turns or the coilswhich are arranged in two layer configuration as shown in FIG. 34, coilswith 9-turn winding number are used.

Therefore, when the yoke length L is shorter, accordingly the width ofthe coils passing through between the magnetic cores is thinner than thewidth of coils with the same winding number arranged in the otherplaces.

Therefore, the width of the coils passing through between the magneticcores changes in accordance with the yoke length L.

Accordingly, it is preferable that the coils to be used for the magnetichead of the present invention passes through a space formed between theopposed first and second magnetic cores via the insulating material, andthe width of the coils passing through the space viewed from an uppersurface (direction of FIG. 34) is narrower than the width of the coilsarranged in the places other than the space. As a result, an increase ofthe coil resistance can be suppressed.

That is, as for the coil portions formed between the magnetic cores, itis necessary to decrease the width of the coils as the yoke length L isshorter. However, when the width of the coils is decreased, the coilresistance is increased.

For this reason, in order to suppress the increase of the coilresistance, a portion which does not require for reducing the width ofthe coils, namely, a portion other than the coil portion formed betweenthe magnetic cores is enlarged.

As a result, the increase of the coil resistance in all the coils can besuppressed.

Since the present invention is characterized particularly in that theyoke width L is set to be not more than 20 μm, it is necessary to reducethe width of the coil portion formed between the magnetic coresparticularly.

Therefore, in the present invention, gaps between the coils are changedsuitably as mentioned above so that the coil resistance is suppressed.This produces a great effect.

In the embodiments in Tables 1 through 3, when the yoke length L becomesshort, in order to make the generated magnetic field of the coils (=coilwinding number×electric current) to be constant with uniform electriccurrent, it is necessary to narrow the width of the coils and make thewinding number to be uniform.

However, in general, since all the coil magnetic fields are absorbed bythe yoke, according to the physical consideration, the output from themagnetic head does not change even if the coils become thin or thick.

FIG. 33 shows results of measuring the output fluctuation (%) in thecase where the width of the coils passing through between the magneticcores is changed in the magnetic head in which the yoke length L is setto 44 μm and the magnetic core 11 serving as an upper core comprisingtwo layers, one of which being the magnetic core 11 a made of67Co8Ni25Fe, while another being the magnetic core 11 b made of82Ni18Fe, the magnetic core 6 serving as the upper shield comprising twolayers, one of which being the magnetic core 6 a made of 67Co8Ni25Fe,while another being the magnetic core 6 b is made of 8Ni18Fe,

As understood from FIG. 33, even if the width of the coil is changed,the output fluctuation in the magnetic head is not influenced.

This shows that the generated magnetic field of the coils is not relatedto the width of the coils, and the change in the width of the coilscannot become a physical factor which can affect the output fluctuationof the magnetic head.

Similarly, in the respective embodiments of the present invention, it isfound that when the composition composing the magnetic core is changed,the value of magnetostriction is also changed.

However, as shown in FIG. 32, similarly to FIG. 18, comparativeexperiment was conducted as to the relationship between the yoke lengthL and the value of the output fluctuation with respect to the magneticmaterial films one of which having the magnetostriction being is 5×10⁻⁶and another one having the magnetostriction is 0.5×10⁻⁶.

As a result of examination about the difference, it was found that acondition in that the output fluctuation becomes not more than 1%, issuch that the yoke length L is set at a value not more than 20 μm in anycases.

Therefore, it is understood that when the yoke length L is not more than20 μm, the value of the output fluctuation is not influenced by themagnetostriction.

Therefore, as mentioned above, the effect, which is obtained byshortening the yoke length L in the magnetic head to be not more than 20μm, can be obtained regardless of the other various factors.

Next, a problem of the stress in the steps of manufacturing the magnetichead of the present invention was examined.

As mentioned above, particularly a plated film having larger saturationmagnetization has a strong stress, and the Co—Ni—Fe film occasionallyhas a stress of about 0.8 GPa. For this reason, when the film is toothick, the film is peeled the more.

FIG. 23 is a graph showing a relationship between the film thickness andthe film peeling incidence when the Co—Ni—Fe film having saturationmagnetization of 2 T is deposited by the plating method.

Note that, when the film thickness become a value exceeding over 2 μm,the peeling incidence abruptly increases. That means that in order tomanufacture a recording head having great saturation magnetization, itis necessary that the thickness of the magnetic core should be not morethan 2 μm.

Next, in the case where the magnetic head of the present invention ismanufactured, technical problems relating to the structure of therecording head or production head were examined.

Particularly in the present invention, since it is considered that themanufacturing of the magnetic head by means of the plating method isadvantageous, the plating method was mainly examined.

That is, as mentioned above, in a specific embodiment of the method ofmanufacturing the recording head according to the present invention,will be explained below.

In a method for producing a recording head including a magnetic headcomprising a first magnetic core and a second magnetic core, each beingoppositely arranged to each other, one of ends of said first magneticcore forming a recording gap with one of ends of said second magneticcore, while the another ends of said first and said second magneticcores forming a magnetic couple, and a coil insulated by an insulatingmaterial and provided in a portion formed between said first and saidsecond magnetic cores whereby magnetic fluxes of said first and saidsecond magnetic cores excited by said coil and leaked from saidrecording gap being used for recording information onto a magneticmedium, a method for forming the coil comprises the steps of, the firststep of forming a seed layer on an insulating material film, the secondstep of forming resist patterns on the seed layer, the third step ofdepositing a coil material among the resist patterns by means ofplating, the fourth step of removing the resist patterns therefrom, thefifth step of removing the seed layer which once had been existed underthe resist patterns, and the sixth step of covering the coil materialwith an insulating material, and note that in this process, these stepsare carried out in this order.

In addition, another specific embodiment of the method of manufacturingthe recording head 60 according to the present invention will bedescribed below.

In a method for producing a recording head including a magnetic headcomprising a first magnetic core and a second magnetic core, each beingoppositely arranged to each other, one of ends of said first magneticcore forming a recording gap with one of ends of said second magneticcore, while the another ends of said first and said second magneticcores forming a magnetic couple, and a coil insulated by an insulatingmaterial and provided in a portion formed between said first and saidsecond magnetic cores whereby magnetic fluxes of said first and saidsecond magnetic cores excited by said coil and leaked from saidrecording gap being used for recording information onto a magneticmedium, a method for forming the coil including the steps of, the firststep of forming an insulation film pattern, the second step of forminggroove sections for forming coils on the insulating material filmpattern, the third step of forming a seed layer on the insulationpattern where the groove sections have been formed, the fourth step offorming a coil material on the seed layer by means of plating, the fifthstep of removing the coil material formed on a portion other than thegroove sections and adjusting a height of the surface of the coilmaterial formed on the groove sections and a height of the surface ofthe insulating material film on the portion other than the groovesections so that both heights coincide with each other, and the sixthstep of covering the coil material formed on the portion other than thegroove sections and the surface of the insulation film on the portionother than the groove sections with an insulation material, and notethat in this process, the above-mentioned steps are carried out in thisorder.

In the method of manufacturing the recording head 60 of the presentinvention, it is desirable that the coil material mainly contains Cu andthe seed layer mainly contains Cu.

Further, in the method of manufacturing the recording head of thepresent invention, it is preferable that the seed layer is formed on aprimary layer made of at least one kind of material selected from agroup of Ta, TaN, Ti and TiN in order to prevent dispersion.

There will be detailed below the recording head 60 and the manufacturingmethod thereof according to the present invention as an embodiment.

Namely, FIGS. 1, 2 and 5 are diagrams showing structures of one portionof the recording head 60 according to the first embodiment of thepresent invention as shown in Table 1.

FIG. 1 is a cross sectional view viewed vertically to an ABS surface 40which opposes to the recording medium 31.

FIG. 2 is a plan view taken along the ABS surface 40 (namely, FIG. 1 isa cross section taken along a line A–B in FIG. 2).

In addition, FIG. 5 is a cross sectional view showing one specificembodiment of the structure of the combined head 50 including therecording head 60 of the present invention and a suitable reproductionhead 70.

In FIG. 5, a substrate 1 to be a slider is composed of a combinedceramic 1 a made of alumina and titanium carbide and an alumina film 1b. A GMR head 70 having reproducing function is formed thereon.

The GMR head 70 is disposed between a lower shield 2 made of a patternedCo—Zr—Ta—Cr film having a thickness of 1 μm (having a compositionshowing a soft magnetic characteristic, for example, Co87Zr5Ta5Cr3) andan upper shield 6 via a magnetic separation layer 3 made of alumina andwhich being made of a magnetoresistive effect element 4.

Furthermore, a gap length between the lower shield 2 and the uppershield 6 is 0.12 μm.

The magnetoresistive effect element 4 is, as shown in FIG. 2, comprisesa center area 4 which senses a magnetic field from the recording medium31 and an end area 5 which supplies a bias magnetic field and anelectric current to the center area 4.

The center area 4 is composed of a laminated structure having the GMReffect generally called as a spin-valve effect.

More specifically, the center area 4 is constituted so that a primary Zrfilm (having a thickness of 3 nm), a Pt—Mn film (having a thickness of20 nm), a Co—Fe film (having a thickness of 2 nm), a Cu film (having athickness of 2.1 nm), a Co—Fe film (having a thickness of 0.5 nm), anNi—Fe film (having a thickness of 2 nm) and a Zr film (having athickness of 3 nm) are laminated in this order from the side of thelower shield 2.

A width of the center area 4 is 0.4 μm defining a width of areproduction track.

In addition, the end area 5 comprises a laminated structure of a Co—Ptfilm (having a thickness of 20 nm) as a permanent magnet film and an Aufilm (having a thickness of 50 nm) as an electrode film.

On the other hand, the upper shield 6 can be commonly used as the firstmagnetic core 6 of the recording head 60.

The upper shield 6 is composed of a permalloy film 6 b having athickness of 2 μm and a Co—Ni—Fe film having a thickness of 0.5 μm(having a composition showing the soft magnetic characteristic, forexample, 65Co12Ni23Fe) 6 a.

Further, in the recording head 60 of the present invention, the uppershield 6 is used as the first magnetic core 6, and zero throat height isdefined by a non-magnetic insulating material 10 a which exists via therecording gap 7 made of alumina having a thickness of 0.18 μm formed onthe magnetic core 6.

The non-magnetic insulating material 10 a is made of a photoresist. Thecoil 9 has a two-layered structure made of Cu plated films, and thefirst layer is insulated by the non-magnetic insulating material 10 a,and the second layer is insulated by a non-magnetic insulating material10 b.

The second magnetic core 11 is formed so as to be laid over thestructure which is composed of the coils 9 and the non-magneticinsulating material 10.

The second magnetic core 11 is composed of a Co—Ni—Fe film havingsaturation magnetization of 2 T (having a composition showing the softmagnetic characteristic, for example, 65Co12Ni23Fe). The yoke length ofthe magnetic core 11 is 9.5 μm, and its thickness is 1 μm.

Next, FIGS. 8, 9 and 10 show structural examples of the combined head 50using an one embodiment of the recording head according to the secondembodiments of the present invention as shown in Table 2.

FIG. 8 is a structural diagram viewed from the ABS surface 40 opposedthe recording medium 31.

FIGS. 9 and 10 are cross sectional views (AB section of FIG. 8) whichare vertical to the ABS surface 40.

The combined head 50 in a specific embodiment has a structure in thatone embodiment of the recording heads 60 in the second embodiments and asuitable reproduction head 70 are laminated.

The drawings show that a reproduction head 70 which is composed of thelower shield 2, the GMR element 4 and the upper shield 6 and a recordinghead 60 of the second embodiment in which the upper shield 6 is used asa first magnetic core 6 are formed on the substrate 1 to be a slider.

The zero throat height in the recording head 60 of the specificembodiment, is defined by the non-magnetic insulating material 10 asshown in FIG. 9 and by a non-magnetic insulating material 8 as shown inFIG. 10.

In addition, in this specific embodiment, the coil 9 has asingle-layered structure.

Further, a second magnetic cores 11 of one embodiment of the recordingheads 60 in the present embodiment, has a laminated structure of aCo—Ni—Fe film having saturation magnetization of 2 T (having acomposition showing the soft magnetic characteristic, for example,65Co12Ni23Fe) 11 a and a permalloy film 11 b.

In a more detailed structure of a part of the embodiments of themagnetic core 11 in the second embodiment, the yoke length L of thesecond magnetic core 11 is 9.5 m, the thickness of the Co—Ni—Fe film 11a being 0.6 μm, and the thickness of the permalloy film 11 b being 1 μm.

Next, FIGS. 11 and 12 show examples of partial structures in the thirdembodiment of the present invention as shown in Table 2.

Namely, in the third embodiment of the present invention, similarly tothe second embodiment, the combined head 50 including the recording head60 of the present invention is formed.

FIG. 11 is a plan view showing the structure viewed from the ABS surface40 opposed to the recording medium 31.

FIG. 12 is a cross sectional view showing the structure viewed in across section vertical to the ABS surface 40, namely, a cross sectiontaken along line A–B in FIG. 11.

In a part of example of this embodiment, a combined head comprising aoptional reproduction head 70 consisting the lower shield 2, a GMRelement 4 and an upper shield 6 which are formed on the substrate 1 tobe used as a slider and a recording head 60 of the first embodimentwhich is formed on the reproduction head 70 and in which an upper shield6 is used as a first magnetic core 6.

The structure of the recording gap 7 in a part of the presentembodiments is similar to that in the first embodiment of the presentinvention.

The upper shield 6 is composed of a Co—Ni—Fe film having a thickness of2 μm (having a composition showing the soft magnetic characteristic, forexample 65Co12Ni23Fe).

The second magnetic core 11 is composed of a laminated structure of aCo—Ni—Fe film 11 a having saturation magnetization of 2 T (having acomposition showing the soft magnetic characteristic, for example,65Co12Ni23Fe) and a permalloy film 11 b.

Here, in the present embodiment, the yoke length L of the magnetic core11 is 9.5 μm, the film thickness of the Co—Ni—Fe film 11 a is 0.6 μm,and the thickness of the permalloy 11 b is 1 μm.

On the other hand, FIGS. 13 and 14 are diagrams showing the combinedhead 50 including the recording head 60 according to a fourth embodimentof the present invention.

FIG. 13 is a plan view showing the structure viewed from the ABS surface40 opposed to the recording medium 31.

FIG. 14 is a cross section vertical to the ABS surface 40 opposed to therecording medium 31, namely, a cross section taken along line A–B inFIG. 13.

The present embodiment shows the structure that the recording head 60 inwhich an upper shield 6 is used as a first magnetic core 6, as the samemanner as shown in the above-mentioned embodiment, is mounted onto areproduction head 70 consisting the lower shield 2, a GMR element 4 andan upper shield 6 which are formed on the substrate 1 to be used.

The structures of the recording gap 7 and the second magnetic core 11are the same as those in the first embodiment of the present invention.

In addition, the upper shield 6 in the recording head in one example ofthe present embodiments is a Co—Ni—Fe film having a thickness of 2 μm(having a composition showing the soft magnetic characteristic, forexample, 65Co12Ni23Fe).

As explained above, as for the respective samples according to theabove-mentioned respective embodiments, the composition, themanufacturing method, the saturation magnetization, themagnetostriction, specific resistance of the magnetic films composingthe upper shield 6 (6 a, 6 b) and the second magnetic core 11 (11 a, 11b) as used and obtained data of the characteristic values relating tothe reproducing function by measuring same in changing the filmthickness and the yoke length L of the magnetic films are shown in Table1, and the characteristic values of the conventional combined head whichhaving a yoke length being longer than that in the present embodiment inTable 1, as comparative data.

As is clear from the above-mentioned comparative experimental results,the low-noise characteristic and the satisfactory high-frequencycharacteristic of the present invention are clear, and the 0/Wcharacteristic is also sufficient.

Next, the method of manufacturing the recording head 60 of the presentinvention will be examined.

The recording head in which the yoke length L is not more than 20 μm hasnot been conventionally manufactured.

Moreover, in order to manufacture a magnetic core with short yoke lengthL, width, thickness of the coils, coil gap, a positional relationshipbetween an insulating material for insulating the coils and the coils,thickness of the insulating material or the like should be set suitably.

Among them, the width and thickness of the coil and the coil gap are setarbitrary with respect to required coil winding number and coilresistance.

At this time, exposure resolution at the time of forming a coil patternmainly defines the limit.

In addition, in a case where the coil resistance becomes too large, asmentioned above, it is effective to set the coil width on the coilportion which does not pass through between the magnetic cores as shownin FIG. 33 to be wider than the coil width of the coil portion whichpasse through between the magnetic cores.

On the other hand, as the yoke length L becomes shorter, it is necessaryto change the volume of the insulating material for insulating the coilssuitably.

Note that, when the thickness of the insulating material becomes toothin, there arises a problem of defective coil insulation.

Therefore, various samples were created, and their drape of theoutermost coils and drape of the coil upper surface which easily causethe defective coil insulation were evaluated.

The evaluated results are shown in FIG. 25. Namely, FIG. 25 showsrelationships between a ratio W1/d whereby a distances W1 and W2 (μm)measured from the outermost coils to the end of the insulating material10 covering the coils 9 from the upper side thereof as shown in FIG. 1,for example, is compared with a thicknesses d of the coils 9 (μm), and apercentage of generation of the defective insulation, with respect to anoptimal positional relationship among each one of portions of therecording head 60.

The method of manufacturing the coils and the insulating material atthis time is composed of, for example as shown in FIG. 30, (a) the stepof forming a seed layer 13 on an insulation film 12, (b) the step offorming resist patterns 14 on the seed layer, (c) the step of formingcoil materials 15 among the resist patterns by means of plating, (d) thestep of removing the resist patterns, (e) the step of removing the seedlayer once existed under the resist patterns and (f) the step ofcovering the coils with an insulating material 16 by means of resist.

Namely, as shown in FIG. 25, the defective insulation is almosteliminated when W1/d is not less than 0.5.

This is because when the distance from the end of the coils to the endof the insulating material is secured sufficiently for the thickness ofthe coils 9, a covering factor at a corner portion of the outermost coil9 is secured sufficiently.

This tendency is applied also to W2/d, W1′/d′ and W2′/d′ in thestructure of the recording head 60 of the present invention shown inFIGS. 1 through 3.

On the other hand, FIG. 26 shows a relationship between a ratio h/d of athickness h (μm) of the insulating material for covering the coils 9 onthe coils 9 to a thickness d (μm) of the coils and a percentage of thedefective insulation.

The method of manufacturing the coil section is the same as that in FIG.25. The defective insulation is almost eliminated when h/d is not lessthan 0.2.

This is because when the film thickness of the resist on the coils 9 isthin, unevenness among the coil remains on the surface, and a coveringfactor is not sufficient at the corners of the coils 9.

This tendency is applied to lower layer coils and upper layer coils whenthe coils has a two-layered structure as shown in FIG. 3, for example.

In addition, a condition in that W1/d≧0.5 where the defective insulationis eliminated as shown in FIG. 25, can be held when h/d≧0.2 shown inFIG. 26.

Namely, in the recording head of the present invention, when thethickness of the coils 9 is d (μm) and the distances from the outermostend coil 9 to the end of the insulating material 10 for covering thecoils 9 are W1 and W2 (μm), it is desirable that the distances W1 and W2(μm) satisfy the following relationships:W1/d≧0.5 and W2/d≧0.5.

Further, in the recording head 60 of the present invention, when thethickness of the coil 9 is d (μm) and the thickness of the insulatingmaterial 10 for covering the coil 9 on the coil is h (μm), it isdesirable that the thickness h (μm) satisfies the followingrelationship:h/d≧0.2.

In the case where the structure and the step of covering the coils 9using the resist 10 are used as mentioned above, the above prescriptionsare required. For example, in the case of i-beam stepper exposure, thewidth and gaps of the coils capable of being manufactured at the abovestep are estimated at 0.8 μm and 0.3 μm respectively.

These are realizable dimensions which can be estimated from that theresist pattern requires a height of about 2 μm and adhesive propertiesof the resist pattern at the time of plating are required in order tosecure the coil thickness of about 1 μm.

At this time, when the coils 9 have a two-layered structure in that acoil in the lower layer has 5 turns while and a coil in an upper layerhas 4 turns, the yoke length becomes about 10 μm.

The combined head 50 produced by the present invention is shown in FIG.5, for example.

It is desirable that a method which realizes a shorter yoke comprises,as shown in FIG. 31, (a) the step of forming an insulating material filmpattern 17, (b) the step of forming resist patterns 18 as the step offorming groove sections for forming coils on the insulating materialfilm pattern, (c) the step of etching by means of the resist patterns,(d) the step of removing the resist patterns, (e) the step of forming alower primary layer 19 a seed layer 20 on the insulating materialpattern where the groove sections are formed, (f) the step of forming acoil material 21 on the seed layer by means of plating, (g) the step ofremoving the coil material formed on places other than the groovesections by means of polishing process and adjusting a height of thesurfaces of coil materials 22 and a height of the surface of theinsulating material film other than the groove sections so that the bothheights having the same level as each other, and (h) the step ofcovering the coil materials formed in the groove sections and thesurface of the insulating material film other than the groove sectionswith an insulating material 23.

According to this method, since a thickness of the resist for patterningthe insulating material film 17 is about 1 μm, the width and gaps of thecoils can be about 0.3 μm and 0.3 μm respectively.

Namely, according to the manufacturing method, the coils can bemanufactured so that their width and gaps are more precise.

In addition, this method is not restricted by the relationship between Wand d and the relationship between h and d which are the prescriptionsin the method of FIG. 30.

With this manufacturing method, the magnetic core with the yoke length Lof not more than 20 μm can be produced, and further the magnetic corewith yoke length L of not more than 5 μm can be produced. The combinedhead which is manufactured by this method is shown in FIG. 15.

As shown in FIGS. 16 and 17, the combined head 50 using the recordinghead 60 manufactured in the present invention can be constituted so thatthe reproduction head 70 and the recording head 60 are independent, andthus the upper shield 6 and the lower recording core 6 are independent.

The structure of a magnetic recording/reproduction apparatus 80 to whichthe combined head 50 of the present invention is mounted is shown inFIG. 29. A head 32 of the present invention is installed by ansuspension 33 and an arm 34 so as to be opposed to a magnetic recordingsurface of a magnetic medium 31 rotating by a driving-use motor 30. Thehead 32 is tracked by a voice coil motor (VCM) 35.

As shown in FIG. 28, the head 32 is composed of a slider 25, electrodes27 and a recording/reproduction element (combined head) 26. Therecording/reproduction operation is performed by a signal transmittedfrom a recording/reproduction channel 38 to the head.

The recording/reproduction channel 38, the VCM 935 for locating the headand the driving motor 30 for rotating the medium are linked by a controlunit 37.

Next, there will be detailed below the method of manufacturing thecombined head 50 according to one embodiment of the present inventionwith reference to FIG. 5 and the above-mentioned various conditions.

Namely, an alumina film 1 b as an insulating material is formed on acombined ceramic la composed of alumina and titanium carbide to be asubstrate 1 as a slider by the sputtering method.

Thereafter, a GMR head 70 having a reproducing function and an ID head60 having a recording function are formed in this order.

The GMR head 70 which serves as the reproduction head 70 of the presentembodiment is formed in the following procedure.

At first, after a Co—Ta—Zr film to be a lower shield 2 is formed into athickness of 1 μm by the sputtering method, this film is etched by anion beam using a photoresist mask so that a pattern is formed.

Next, an alumina film for forming a reproduction gap 3 corresponding toa magnetic separation layer into a thickness of 0.03 μm by thesputtering method.

Thereafter, a spin-valve laminated structure to be a center area 4 isformed thereon by the sputtering method. The spin-valve laminatedstructure is formed in a manner that a primary Zr film (having athickness of 3 nm), a Pt—Mn film (having a thickness of 20 nm), a Co—Fefilm (having a thickness of 2 nm), a Cu film (having a thickness of 2.1nm), a Co—Fe film (having a thickness of 0.5 nm), an Ni—Fe film (havinga thickness of 2 nm) and a Zr film (having a thickness of 3 nm) arelaminated from on the side of the lower shield 2 in this order. Further,the structure is etched by an ion beam using a photoresist mask so thata pattern is formed.

Next, a laminated structure film to be an end area 5 composed of a Co—Ptfilm (thickness: 20 nm) and an Au film (thickness: 50 nm) is formed bythe sputtering method using this photoresist mask, and the photoresistmask is lifted off so that an MR element 4 is finished.

An alumina film for forming another reproduction gap 3 is formed into athickness of 0.057 μm on the MR element 4 by the sputtering method. Thereproduction gap length is 0.12 μm.

On the other hand, the ID head 60 of the present invention is formed inthe following procedure.

Namely, an upper shield 6 which serves also as a recording electrode isformed by a method of growing a plated film in a frame of a photoresist.

Plating bath conditions of a permalloy film composing the upper shield 6b used in the present embodiment are as follows:

Name Concentration (mol/L) Nickel chloride 0.16 Nickel sulfate 0.08Sodium Chloride 0.42 Boron 0.40 Na saccharin 0.0072 Ferrous sulfate0.0045 Na lauryl sulfate 0.00035 36% hydrochloric acid 0.0017 PH 2.6Current density 6 mA/cm²

Further, plating bath conditions of the Co—Ni—Fe film composing theupper shield 6 a are as follows:

Name Concentration (mol/L) Cobalt sulfate 0.092 Nickel sulfate 0.20Ammonium chloride 0.28 Boron 0.40 Ferrous sulfate 0.0016 Na laurylsulfate 0.00035 80% sulfonic acid 0.0012 PH 2.8 Current density 15mA/cm²

The above-mentioned first magnetic core 6 also serves as the uppershield 6, and a recording gap 7 made of alumina with a film thickness of0.18 μm is deposited on the upper shield 6 by the sputtering method.

A first layer of coils 9 is formed thereon by a method of growing a Cuplated film in a frame of a photoresist, and a non-magnetic insulatingmaterial 10 a made of photoresist is formed. A second layer of the coils9 is formed in the same manner, and a non-magnetic insulating material10 b made of photoresist is formed.

These steps are shown in FIG. 30.

When a magnetic core with yoke length L of 9.5 μm is produced, as shownin FIG. 5, it has a two-layered coils structure of a 5-turn first layerand a 4-turn second layer. As a result, the magnetic core can beproduced with a coil thickness of 1 μm, a coil width of 1 μm and a coilgap of 0.3 μm.

At this time, W1 and W2 shown in FIG. 4 become 1.4 μm when throat heightis 0.5 μm. W1 and W2 satisfy the relationships: W1/d≧0.5, W2/d≧0.5,W′/d≧0.5 and W2′/d≧0.5.

In addition, in order to satisfy h/d≧0.2, H′/d′≧0.2, h(h′)≧0.2μ, and themagnetic core can be manufactured sufficiently under these conditions.

The coil resistance at this time was about 18Ω.

As a cross section of the coils is smaller, the resistance increases,but a coil width on a portion which does not cross the magnetic core isenlarged so that the resistance value can be maintained small.

In FIG. 5, when d and d′ are 1 μm, and h and h′ are 0.5 μm, the heightsof the structures of the two-layered coils and the insulating materialbecome 3 μm.

Conventionally since it is standard that the coil width is 2 μm, thecoil thickness is 2 μm and the thickness of the insulating film on thecoils is about 2 μm in the head with long yoke length L, the heights ofthe two-layer coils and the insulating material are about 8 μm.

In the recording head 60 of the present invention, when the magneticcore 11, a level difference in the heights between the coils and theinsulating material could be greatly reduced from 8 μm to 3 μm.

When the second magnetic core 11 is formed, as shown in FIG. 27, aphotoresist 28 is applied to the level difference between thecoils/insulating material.

At this time, it was conventionally necessary to apply a resist of about5 μm in order to form the magnetic core with film thickness of about 3μm. However, a resist thickness in a vicinity of ABS where a patternshould be formed with the most narrow width for determining therecording width reached about 10 μm due to an influence of the leveldifference. Therefore, the most narrowest width where a pattern can beformed in the conventional head was about 1 μm.

On the contrary, in the recording head 60 of the present invention, thelevel difference between the coils and insulating material is low, i.e.,about 3 μm, and the film thickness of the magnetic core can be thin. Asa result, the resist thickness in the vicinity of ABS is not more than 5μm, and a pattern of about 0.5 μm can be formed.

On the other hand, a second magnetic pole 11 used a Co—Ni—Fe film withBs of 2 T. The plating bath conditions of the Co—Ni—Fe film are asfollows:

Name Concentration (mol/L) Cobalt sulfate 0.092 Nickel sulfate 0.20Ammonium chloride 0.28 Boron 0.40 Ferrous sulfate 0.0016 Na laurylsulfate 0.00035 80% sulfonic acid 0.0012 PH 2.8 Current density 15mA/cm²

Next, a fifth embodiment of the present invention shown in Table 3 isshown as the structure of the combined head 50 in FIG. 15.

The structures of the substrate 1 to be a slider, the lower shield 2,the GMR element 4, the recording gap 7 and the upper shield 6 are thesame as those in the first embodiment of the present invention. The yokelength L in the present invention is 5 μm. The present embodiment andcomparative example 15 of the head of the present invention are shown inTable 3.

There will be described below a manufacturing method of the fifthembodiment. In the present embodiment, a completely new method shown inFIG. 31 is used for the method of manufacturing the coils 9 and theinsulating materials 10 a and 10 b.

At first, an SiO₂ film with a thickness of 1 μm were deposited on thealumina film composing the recording gap 7 so that a pattern 17 wasformed (FIG. 31( a)).

Next, resist patterns 18 were formed on the SiO₂ insulating materialfilm pattern 17 at the step of forming groove sections for forming coils(FIG. 31( b)).

Next, etching was carried out by using the resist pattern and CF4 gas(FIG. 31( c)). The etching depth was 0.8 μm.

Next, the resist pattern was removed (FIG. 31( d)), a TaN primary layer19 and a Cu seed layer 20 were formed on the insulating material patternwhere the groove sections were formed (FIG. 31( e)). A Cu film 21 wasformed on the seed layer by plating (FIG. 31( f)).

Next, the Cu film formed on a portion other than the groove sections wasremoved by mechanical abrasion, and the height of the surface of the Cufilm 22 formed in the groove sections and the height of the surface ofthe insulating material film on the portion other than the groovesections was arranged so as to be level with each other (FIG. 31( g)).

Finally, the Cu coils formed in the groove sections and the surface ofthe insulating material film on the portion other than the groovesections were covered with an SiO₂ insulating material 23 with a filmthickness of 0.2 μm so that a structure of the coils and the insulatingmaterial was finished.

With this method, the coil width is 0.4 μm, the coil thickness (height)is 0.7 μm, the coil gap is 0.3 μm, throat height is 0.5 μm, and SiO₂width between the side surface of the outermost coils and the magneticcore is 0.65 μm so that the yoke length of 5 μm is realized.

In addition, the height of the structure of the coils and the insulatingmaterial was only 1.1 μm. Due to this low level difference, the patternwith width of about 0.3 μm could be formed in the vicinity of the ABSsurface.

Therefore, this process is effectively only to form the magnetic corewith short yoke length but also to manufacture the magnetic head withnarrow track width.

Next, the structure of the combined head according to a sixth embodimentof the present invention is shown in FIGS. 16 and 17.

Namely, FIG. 16 is a plan view showing the structure viewed from the ABSsurface 40 opposed to the recording medium 31. FIG. 17 is a crosssection vertical to the ABS surface 40, namely, a cross section takenalong line A–B in FIG. 16.

In the present embodiment, the upper shield 6′ of the reproduction GMRhead 70 and the lower magnetic core 6 of the recording head 60 areindependent, and they are separated by a non-magnetic layer 24.

The upper shield 6′ in the present embodiment is a permalloy film with athickness of 2 μm.

In addition, its yoke length L is 9.5 μm, the lower magnetic core 6 andthe upper magnetic core 11 are composed of a Co—Ni—Fe film with athickness of 1 μm (having a composition showing the soft magneticcharacteristic, for example, 65Co12Ni23Fe).

Also in the combined head 50 of the present embodiment, the outputfluctuation according to the recording operation was not more than 0.5%,30% Roll-off frequency of the inductance was 390 MHz and 0/W was 45 dB,that was satisfactory.

On the other hand, a seventh embodiment of the present invention is amagnetic recording/reproduction apparatus 80 to which the combined head50 including the recording head 60 of the present invention is mounted.

As shown in FIG. 29, a head 32 of the present invention is installed byan suspension 33 and an arm 34 so as to be opposed to the magneticrecording surface of a magnetic medium 31 rotated by a driving motor 30,and the head 32 is tracked by a voice coil motor (VCM) 35.

As shown in FIG. 28, the head 32 is composed of a slider 25, anelectrode 27 and a recording/reproduction element (combined head) 26.

The recording/reproduction operation is performed by a signal from arecording/reproduction channel 38 of the head. Therecording/reproduction channel, VCM for locating the head and thedriving motor for rotating the medium are linked by a control unit 37.

The magnetic recording/reproduction apparatus is a storage device withhigh density and large capacity and also a storage device which isadvantageous to data transmission at high speed.

Further, the combined head 50 is characterized in that one of first andsecond magnetic cores serves also as a first magnetic shield, and amagnetoresistive effect element 4, which is provided between the firstmagnetic shield (upper shield) and a second magnetic shield (lowershield) opposed to the first magnetic shield, carries out reproduction,and recording is carried by the recording head 60.

In addition, the combined head 50 is characterized in that themagnetoresistive effect element 4, which is provided between the firstmagnetic shield (upper shield) and the second magnetic shield (lowershield) opposed to each other, carries out reproduction, and recordingis carried out by the recording head 60 laminated on the element 4.

The magnetic recording/reproduction apparatus 80 according to the aboveembodiment of the present invention is constituted so that the combinedhead 50 is mounted thereinto.

According to the present invention, in the first place even in the casewhere the Co—Ni—Fe film or 45NiFe film with great saturationmagnetization for realizing high recording ability is applied to theupper shield of the combined head, the recording head and the combinedhead where a reproduction noise is suppressed are realized.

In the second place, the Co—Ni—Fe film which can obtain saturationmagnetization of 2 T is used as the magnetic core material with greatsaturation magnetization so that the recording head, in which the highsaturation magnetization characteristic of the Co—Ni—Fe film can beutilized as a recording characteristic maximally, is provided.

In the third place, the recording head in which the recordingperformance is high at high frequency is provided.

In the fourth place, the recording head, in which the track width isnarrow according to high-density recording, can be provided.

In the fifth place, the methods of manufacturing the recording head andthe combined head can be provided.

In the sixth place, the storage device, which is suitable for high-speeddata transmission with large capacity, is realized by the magneticrecording/reproduction apparatus to which the recording head and thecombined head are mounted.

1. A recording head, comprising: a first magnetic core; a secondmagnetic core arranged opposite to said first magnetic core; a recordinggap formed by one end of said first magnetic core and one end of saidsecond magnetic core; a magnetic couple formed by the other ends of saidfirst and second magnetic cores; and a coil, insulated by an insulatingmaterial, between said first and said second magnetic cores, wherebymagnetic fluxes of said first and said second magnetic cores excited bysaid coil and leaked from said recording gap are used for recordinginformation onto a magnetic medium, wherein a yoke length between afront end of said recording head, in proximity of said recording gap,and a contact point of said magnetic couple, is not more than 20 μm;wherein said magnetic material forming each one of said first and saidsecond magnetic cores each opposing to each other, has a configurationin that a plurality of magnetic material layers are laminated with eachother and further wherein, with respect to the yoke length L (unit: μm),a total sum Σ of a product of a saturation magnetization (unit: T) andthe film thickness (unit: μm) of the respective magnetic materialscomposing the respective magnetic cores, (Σ(saturation magnetization(T)×film thickness (μm)) ) satisfies the following relationship:0.05 (T)×yoke length L (μm)+0.5 (T μm)<=SIGMA(saturation magnetization(T)×film thickness (μm)).
 2. A recording head, comprising: a firstmagnetic core; a second magnetic core arranged opposite to said firstmagnetic core; a recording gap formed by one end of said first magneticcore and one end of said second magnetic core; a magnetic couple formedby the other ends of said first and second magnetic cores; and a coil,insulated by an insulating material, between said first and said secondmagnetic cores, whereby magnetic fluxes of said first and said secondmagnetic cores excited by said coil and leaked from said recording gapare used for recording information onto a magnetic medium, wherein ayoke length between a front end of said recording head, in proximity ofsaid recording gap, and a contact point of said magnetic couple, is notmore than 20 μm; and wherein with respect to the yoke length, a productof a saturation magnetization of said first and second magnetic cores,and the film thickness of the magnetic materials composing each of saidfirst and second magnetic cores, respectively, satisfies: 0.05 (T)×yokelength L (μm)+0.5 (T μm)≦saturation magnetization (T)×film thickness(μm) wherein said coil which is configured so as to pass through a spaceformed between said first and said second magnetic cores, oppositelyarranged to each other, via said insulating material, and furtherwherein a width of said coil passing through said space is equal to ornarrower than that of said coil arranged in a portion other than saidspace.
 3. A recording head, comprising: a first magnetic core; a secondmagnetic core arranged opposite to said first magnetic core; a recordinggap formed by one end of said first magnetic core and one end of saidsecond magnetic core; a magnetic couple formed by the other ends of saidfirst and second magnetic cores; and a coil, insulated by an insulatingmaterial, between said first and said second magnetic cores, wherebymagnetic fluxes of said first and said second magnetic cores excited bysaid coil and leaked from said recording gap are used for recordinginformation onto a magnetic medium, wherein a yoke length between afront end of said recording head, in proximity of said recording gap,and a contact point of said magnetic couple, is not more than 20 μm; andwherein with respect to the yoke length, a product of a saturationmagnetization of said first and second magnetic cores, and the filmthickness of the magnetic materials composing each of said first andsecond magnetic cores, respectively, satisfies: 0.05 (T)×yoke length L(μm)+0.5 (T μm)≦saturation magnetization (T)×film thickness (μm),wherein said coil which is configured so as to pass through a spaceformed between said first and said second magnetic cores, oppositelyarranged to each other, via said insulating material, and furtherwherein a width of said coil is optionally changed so that a resistancevalue of said coils becomes smaller than that of said coil said widththereof being set at constant value.
 4. A method of manufacturing arecording head, which comprises: a first magnetic core; a secondmagnetic core arranged opposite to said first magnetic core; a recordinggap formed by one end of said first magnetic core and one end of saidsecond magnetic core; a magnetic couple formed by the other ends of saidfirst and second magnetic cores; and a coil, insulated by an insulatingmaterial, between said first and said second magnetic cores, wherebymagnetic fluxes of said first and said second magnetic cores excited bysaid coil and leaked from said recording gap are used for recordinginformation onto a magnetic medium, wherein a yoke length between afront end of said recording head, in proximity of said recording gap,and a contact point of said magnetic couple, is not more than 20 μm; andwherein with respect to the yoke length, a product of a saturationmagnetization of said first and second magnetic cores, and the filmthickness of the magnetic materials composing each of said first andsecond magnetic cores, respectively, satisfies:0.05 (T)×yoke length L (m)+0.5 (T μm)≦saturation magnetization (T)×filmthickness (μm), said method comprising; forming a seed layer on aninsulating material film; forming resist patterns on said seed layer;depositing a coil material among said resist patterns by means ofplating; removing said resist patterns therefrom; removing said seedlayer; and covering said coil material with an insulating material. 5.The method according to claim 4, wherein covering said coil materialwith an insulating material is carried out by spin coating process. 6.The method according to claim 4, wherein assuming that a thickness ofsaid coils being d (μm) and distances from said outermost coil to an endof said insulation material covering said coils being W1 and W2 (μm),respectively, said distances W1 and W2 (μm) satisfy said followingrelationships, respectively:W1/d≧0.5 and W2/d≧0.5.
 7. The method according to claim 4, whereinassuming that a thickness of said coil being d (μm) and a thickness ofsaid insulating material covering said coil on said coil being h (μm),said thickness h (μm) satisfies said following relationship:h/d≧0.2.
 8. A method of manufacturing a coil on a recording head, whichcomprises: a first magnetic core; a second magnetic core arrangedopposite to said first magnetic core; a recording gap formed by one endof said first magnetic core and one end of said second magnetic core; amagnetic couple formed by the other ends of said first and secondmagnetic cores; and the coil, insulated by an insulating material,between said first and said second magnetic cores, whereby magneticfluxes of said first and said second magnetic cores excited by said coiland leaked from said recording gap are used for recording informationonto a magnetic medium, wherein a yoke length between a front end ofsaid recording head, in proximity of said recording gap, and a contactpoint of said magnetic couple, is not more than 20 μm; and wherein withrespect to the yoke length, a product of a saturation magnetization ofsaid first and second magnetic cores, and the film thickness of themagnetic materials composing each of said first and second magneticcores, respectively, satisfies:0.05 (T)×yoke length L (μm)×0.5 (T μm)≦saturation magnetization (T)×filmthickness (μm), said method comprising; forming an insulation film;forming groove sections for forming coils on said insulation; forming aseed layer on said insulation film where said groove sections have beenformed; forming a coil material on said seed layer by means of plating;removing said coil material formed on a portion other than said groovesections and adjusting a height of said surface of said coil materialformed on said groove sections and a height of said surface of saidinsulation film so that both heights coincide with each other; andcovering said coil material formed in said groove sections and saidsurface of said insulation film with an insulation material.
 9. Themethod according to claim 4, wherein said seed layer is mainly formedwith Cu, and said seed layer is formed on a primary layer composed of atleast one kind of elements selected from a group of Ta, TaN, Ti and TiN.10. A combined head comprising: a first magnetic core; a second magneticcore arranged opposite to said first magnetic core; a recording gapformed by one end of said first magnetic core and one end of said secondmagnetic core; a magnetic couple formed by the other ends of said firstand second magnetic cores; and a coil, insulated by an insulatingmaterial, between said first and said second magnetic cores, wherebymagnetic fluxes of said first and said second magnetic cores excited bysaid coil and leaked from said recording gap are used for recordinginformation onto a magnetic medium, wherein a yoke length between afront end of said recording head, in proximity of said recording gap,and a contact point of said magnetic couple, is not more than 20 μm; andwherein with respect to the yoke length, a product of a saturationmagnetization of said first and second magnetic cores, and the filmthickness of the magnetic materials composing each of said first andsecond magnetic cores, respectively, satisfies: 0.05 (T)×yoke length L(μm)+0.5 (T μm)<=saturation magnetization (T)×film thickness (μm),wherein said coil which is configured so as to pass through a spaceformed between said first and said second magnetic cores, oppositelyarranged to each other, via said insulating material, and furtherwherein a width of said coil is optionally changed so that a resistancevalue of said coils becomes smaller than that of said coil said widththereof being set at constant value, either one of said first and secondmagnetic cores is used as a first magnetic shield, while a reproducedprocess can be carried out by a magnetoresistive effect element which isprovided between said first magnetic shield and a second magnetic shieldoppositely arranged to said first magnetic shield.
 11. A combined headaccording to claim 10, wherein a relationship between a reproductionoutput of said magnetoresistive effect element and a standard deviationof said out put of said satisfies the following formula; (standarddeviation) (average of reproduction outputs)≦0.01.
 12. A magneticrecording/reproduction apparatus which is provided with said combinedhead according to claim 10.